Step 1: Understanding the Question:
The question asks us to identify the core attribute of the Natural Law theory from the given options.
Step 2: Key Concepts and Approach:
Natural Law theory is built on the premise that law and morality are fundamentally connected.
We must look for the statement that reflects this intrinsic moral foundation of law and contrast it with positivist theses.
Step 3: Detailed Explanation:
• Lex Iniusta Non Est Lex: This Latin maxim translates to "An unjust law is not a law." It is a foundational tenant of classical Natural Law theory, famously propounded by St. Augustine and later integrated by St. Thomas Aquinas.
• Evaluating Option B: Natural laws are not commands of human beings; rather, they are derived from reason, nature, or divine source. Human commands are associated with legal positivism.
• Evaluating Option C (Pedigree Thesis): The pedigree thesis is an attribute of Legal Positivism, stating that a rule is legally valid if it is derived from a recognized source, regardless of its moral content.
• Evaluating Option D (Separability Thesis): The separability thesis is also a core positivist attribute, asserting that there is no necessary conceptual connection between law and morality.
• Conclusion: Only Option A represents an attribute of Natural Law theory.
Step 4: Final Answer:
The attribute of Natural Law theory is "Lex injusta is non est law." Therefore, Option A is the correct choice.